Home > Publications database > Silicon nanowire transistor arrays for biomolecular detection |
Dissertation / PhD Thesis/Book | PreJuSER-15536 |
2011
Forschungszentrum Jülich GmbH, Zentralbibliothek, Verlag
Jülich
ISBN: 978-3-89336-739-9
Please use a persistent id in citations: http://hdl.handle.net/2128/15310
Abstract: Biosensors based on nano-scale electronic devices have the potential to achieve exquisite sensitivity for the direct detection of biomolecular interactions. Silicon nanowire fieldeffect transistor (SiNW-FET) is the most promising candidates for these purposes because of their biocompatibility, very high surface-to-volume ratio, fast response, and good reliability of the signal. In the last few years, several promising results based on SiNW sensors, which were either fabricated by “top-down” or “bottom-up” methods, have been reported, such as biosensors for protein binding, DNA hybridization or the detection of extracellular signals from electrogenic cell. The aim of this work was to fabricate SiNW arrays in a large scale with robust methods and then apply for the detection of biomolecules. To achieve these tasks, we have developed a novel “top-down” approach for wafer-scale processes of SiNW arrays based on a combination of two technologies: the novel and high throughput nanoimprint lithography and wet anisotropic etching of silicon. Devices were fabricated at the clean room facility at the Institute of Bio- and Nanosystems (IBN), Research Center Juelich, Germany. By our approach, the dimensions of the SiNWs can simply be tuned using different etching times of the sub-processes. This process offers a large dimension control of the desired nanowire structures without using an expensive mask or highly complicated nanostructuring of the devices. For the full fabrication process, we employed thermal nanoimprint lithography and anisotropic etching of Si by tetramethylammonium hydroxide (TMAH) in combination with other micro-fabrication techniques such as wet etching, dry etching and photolithography to create the SiNW array sensors. Two complete fabrication rounds were finalized including top-down structuring, implantation and silicidation of contact lines, passivation of the devices with a high quality SiO2 layer deposited by a “low pressure chemical vapor deposition” (LPCVD) process to enable device operation in liquid environments, gate oxide formation, metallization. Finally, chips were wire bonded and encapsulated with epoxy glue enabling stable and reliable operation within electrolyte environments. Main advantages of our fabrication protocol are that the sensors could achieve high sensitivity, while possible mass production and reproducibility of the devices are guaranteed. The chip designs were based on either 4×4 arrays for the first round or 28×2 arrays for the second round [...]
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